Without limiting the scope of the present invention, its background is described with reference to the production of hydrocarbons through a wellbore traversing an unconsolidated or loosely consolidated formation, as an example.
It is well known in the subterranean well drilling and completion art that particulate materials such as sand may be produced during the production of hydrocarbons from a well traversing an unconsolidated or loosely consolidated subterranean formation. Numerous problems may occur as a result of the production of such particulate materials. For example, the particulate materials cause abrasive wear to components within the well, such as tubing, flow control devices and safety devices. In addition, the particulate materials may partially or fully clog the well creating the need for an expensive workover. Also, if the particulate materials are produced to the surface, they must be removed from the hydrocarbon fluids by processing equipment at the surface.
One method for preventing the production of such particulate materials is gravel packing the well adjacent the unconsolidated or loosely consolidated production interval. In a typical gravel pack completion, a sand control screen is lowered into the wellbore on a work string to a position proximate the desired production interval. A fluid slurry including a liquid carrier and a particulate material, such as gravel, is then pumped down the work string and into the well annulus formed between the sand control screen and the perforated well casing or open hole production zone.
The liquid carrier either flows into the formation, returns to the surface by flowing through the sand control screen or both. In either case, the gravel is deposited around the sand control screen to form a gravel pack, which is highly permeable to the flow of hydrocarbon fluids but blocks the flow of the particulate carried in the hydrocarbon fluids. As such, gravel packs can successfully prevent the problems associated with the production of particulate materials from the formation.
It has been found, however, that a complete gravel pack of the desired production interval is difficult to achieve particularly in extended or deviated wellbores including wellbores having long, horizontal production intervals. These incomplete packs are commonly a result of the liquid carrier entering a permeable portion of the production interval causing the gravel to dehydrate and form a sand bridge in the annulus. Thereafter, the sand bridge prevents the slurry from flowing to the remainder of the annulus which, in turn, prevents the placement of sufficient gravel in the remainder of the production interval.
In addition, it has been found that gravel packing is not feasible in certain open hole completions. Attempts have been made to use expandable metal sand control screens in such open hole completions. These expandable metal sand control screens are typically installed in the wellbore then radially expanded using a hydraulic swage or cone that passes through the interior of the screen or other metal forming techniques. In addition to filtering particulate materials out of the formation fluids, one benefit of these expandable sand control screens is the radial support they provide to the formation which helps prevent formation collapse. It has been found, however, that conventional expandable sand control screens do not contact the wall of the wellbore along their entire length as the wellbore profile is not uniform. More specifically, due to the process of drilling the wellbore and heterogeneity of the downhole strata, washouts or other irregularities commonly occur which result in certain locations within the wellbore having larger diameters than other areas or having non circular cross sections. Thus, when the expandable sand control screens are expanded, voids are created between the expandable sand control screens and the irregular areas of the wellbore, which has resulted in incomplete contact between the expandable sand control screens and the wellbore. In addition, with certain conventional expandable sand control screens, the threaded connections are not expandable which creates a very complex profile, at least a portion of which does not contact the wellbore. Further, when conventional expandable sand control screens are expanded, the radial strength of the expanded screens is drastically reduced resulting in little, if any, radial support to the borehole.
Therefore, a need has arisen for a sand control screen assembly that prevents the production of particulate materials from a well that traverses a hydrocarbon bearing subterranean formation without the need for performing a gravel packing operation. A need has also arisen for such a sand control screen assembly that provides radial support to the formation without the need for expanding metal tubulars. Further, a need has arisen for such a sand control screen assembly that is suitable for operation in long, horizontal, open hole completions.